The proposed projects will be part of a long-range program, now in progress, on the anatomy of the visual pathways and centers in primates. The goals of the projects are to investigate the termination of intrinsic, association and callosal fibers in the visual cortices of primates. This will be achieved by placing lesions in the visual cortices and subsequently studying the degenerative processes of axonal boutons of efferent fibers at the ultrastructural level. The knowledge obtained during the course of these projects should help to elucidate the circuitry of the visual cortices and advance our understanding of their functions.